1. Field
Example embodiments may relate to a method of testing semiconductor devices. More particularly, example embodiments may relate to a method of testing semiconductor devices by identifying units of lots and a test tray such that a plurality of lots having the semiconductor devices may be continuously tested by a handler.
2. Description of the Related Art
A handler may be used to electrically test semiconductor devices. A handler may be an automatic testing robot, which may be electrically connected to a tester. The handler may connect semiconductor devices to the tester, perform electrical tests, and sort the semiconductor devices according to electrical test results.
The handler may use a carrier, for example, a tray to convey the semiconductor devices. The tray may have a structure configured so that a plurality of semiconductor devices may be inserted in a matrix. The tray may be a customer tray used for transportation and storage, or a test tray for connecting to the tester.
FIG. 1 is a block diagram of a handler according to the conventional art. Referring to FIG. 1, a handler 50 may include a test front area 10 having a customer tray 16 and a test chamber 30. Semiconductor devices may move in the direction indicated by arrows while in the customer tray so that electrical testing may be performed in the handler 50.
Semiconductor devices may be inserted in units of lots into a first customer tray 16 of a loading portion 12 of the test front area 10. The semiconductor devices may be conveyed from the customer tray 16 to a test tray 20 so as to electrically test the semiconductor devices at a tray-conveying site 18 of the loading portion 12.
The semiconductor devices may be conveyed to a soak portion 32 where various temperatures may be applied to the semiconductor devices. The temperatures at the soak portion 32 may include room temperature, and temperatures lower and higher than room temperature. The semiconductor devices may be conveyed to a test portion 36. The semiconductor devices may be connected to a tester for electrical testing.
The semiconductor devices may be conveyed to a sorting portion 38, inserted into a second customer tray 25, and sorted according to test results into defective semiconductor devices 26 and non-defective semiconductor devices 24. The sorted semiconductor devices may be removed at an unloading portion 22 of the handler 50.
FIG. 2 is a flowchart illustrating a method of electrically testing a semiconductor device with a handler connected to a tester according to the conventional art. Referring to FIG. 2, a test program may be loaded onto a tester in operation T10. The tester and the handler may be electrically connected to each other. In order to start electrical testing on the semiconductor devices, the semiconductor devices in units of lots may be input (e.g., loaded) to a customer tray of the handler in operation H10. The semiconductor devices in the customer tray may be conveyed to a test tray in operation H12. The semiconductor devices may be connected to the tester in operation H14, and an electrical test starting signal may be applied to the tester.
The tester may start to perform an electrical test on the semiconductor devices in response to an electrical test starting signal in operation T12, and when the electrical test is completed in operation T14, an electrical test result bin containing the semiconductor devices may be transmitted to the handler in operation T16. Because only one lot may be electrically tested inside the handler, test results of the devices under test (DUT) need not to be separately converted.
The handler sorts the DUT in each bin according to the test results in operation H16. If an electrical test on a DUT is completed, operations of connecting the tester to another DUT (H14′), starting another electrical test (T12′), finishing another test (T14′), and sorting another DUT in the handler (H16′) after transmitting the test results from the tester (T16′) may be repeatedly performed in operation H17.
When the last DUT included in a lot is sorted (H18) and unloading (H20) of a last DUT is finished, the lots may be unloaded (H22) from the handler, thus finishing the electrical test on the loaded lot. The next lot may be loaded (H28), and the above process may be repeated on the next lot (H30).
FIG. 3 is a flowchart illustrating a method of electrically testing a plurality of lots using a handler and a tester according to the conventional art. Referring to FIG. 3, a first lot may be supplied to a handler in operation S10. An electrical test may be performed on the first lot in operation S20. When the electrical test is finished, the first lot may be unloaded from the handler in operation S30. Afterwards, a second lot may be supplied to the handler in operation S40, tested in operation S50, and unloaded in operation S60, thus completing the electrical test on the first lot.
In the method of electrically testing semiconductor devices according to the conventional art, the semiconductor devices may be input to or output from the handler in units of lots. In general, the tester may perform an electrical test on the semiconductor devices by generating an electrical signal, and the handler may physically process the semiconductor devices inserted in trays. However, only one lot may be supplied from the handler, and the tester may not operate while the handler is physically processing, for example, loading and uploading the semiconductor devices. Accordingly, the tester may not be efficiently used due to the down times.
In general, it may take up to about 800 seconds to load and unload one lot in a handler. Because a tester may not operate during this time, the efficiency of a test system including the handler and the tester may be limited.